High-response of NiO-modified self-assembled nanosheets formed with ZnO nanoparticles for n-butanol detection

Heterojunction fabrication is an effective way to improve the performance of gas sensors. In this work, NiO-modified ZnO nanoparticles and self-assembled nanosheets were prepared by a simple one-pot hydrothermal method. The morphological and structural characterizations demonstrated that the addition of NiO increased the surface area and provided more adsorption sites for the reaction. The results of gas sensing tests showed that the response of 1 % NiO-loaded ZnO to n-butanol reached 220 at 200 ℃. In addition, the sensor exhibited better selectivity (4.5 times that of n-butanol for other target gases), repeatability, and long-term (25 days) stability. The gas sensing performance is mainly enhanced by the formation of heterojunctions; the corresponding mechanism is also described.